Tension Calculator
Rope tension for a hanging mass, still or accelerating.
The elevator problem
T = m × (g + a)
At rest, the rope carries exactly the weight: 80 kg is 785 N. Accelerate upward at 2 m/s² and tension jumps to 945 N; accelerate downward and it drops. At a = -9.81 (free fall) tension hits zero, which is why slack climbing rope is a fall in progress.
Beyond the vertical rope
Angled ropes divide the load: two lines at 60° from horizontal each carry T = W / (2 sin 60°), and as the lines approach horizontal the tension blows up toward infinity. You cannot pull a clothesline perfectly straight, and that equation is the reason.